Diagnostic accuracy of protected specimen brush and bronchoalveolar lavage in nosocomial pneumonia: impact of previous antimicrobial treatments.
OBJECTIVE
To determine whether the diagnostic accuracy of bronchoscopy samples in patients with suspected ventilator-associated pneumonia is affected by prior antibiotic treatment given for a previous infection, and/or by antibiotic treatment recently started to treat suspected ventilator-associated pneumonia.


METHODS
Study of critically ill patients.


METHODS
Intensive care unit in a university hospital.


METHODS
Sixty-three episodes of suspected ventilator-associated pneumonia were prospectively evaluated. Based on prior antibiotic treatment, three groups were defined: no antibiotic group (no previous antibiotic treatments), n = 12; current antibiotic group (antibiotic treatment initiated >72 hrs earlier), n = 31; and recent antibiotic group (new antibiotic treatment class started within the last 24 hrs), n = 20.


METHODS
Fiberoptic bronchoscopy with quantitative protected specimen brush cultures, bronchoalveolar lavage cultures, and intracellular organism counts of bronchoalveolar lavage cells.


RESULTS
The diagnosis of ventilator-associated pneumonia was made in 35 cases, based on histology (n = 2), cavitation (n = 2), blood cultures (n = 4), or outcome under appropriate antibiotic treatment (n = 27). The discriminative value of the tests, based on the area under the receiver operating characteristic curve, was high (> or =0.85) in both current antibiotic treatment and recent antibiotic treatment patients. Sensitivities for a 5% intracellular organism count of bronchoalveolar lavage cells, a protected specimen brush culture threshold of 10(3) colony-forming units (cfu)/mL, and a bronchoalveolar lavage culture threshold of 10(5) cfu/mL were as follows, respectively, in the three groups: 0.71, 0.88, and 0.71 (no antibiotic treatment group); 0.5, 0.77, and 0.83 (current antibiotic group); and 0.67, 0.40, and 0.38 (recent antibiotic group). Specificity was consistently > or =0.9. In the recent antibiotic group, protected specimen brush and bronchoalveolar lavage cultures had lower sensitivities (p < .05), and the best threshold values for these two tests were 10(2) cfu/mL and 10(3) cfu/mL, respectively.


CONCLUSIONS
After recent introduction of an antibiotic treatment for suspected ventilator-associated pneumonia, protected specimen brush and bronchoalveolar lavage culture thresholds must be decreased to maintain good accuracy. In contrast, current antibiotic treatment prescribed for a prior infectious disease does not modify the diagnostic accuracy of protected specimen brush or bronchoalveolar lavage.
Souweine
B
B
Service de Réanimation des Maladies Infectieuses, Groupe Hospitalier Bichat-Claude Bernard, Paris, France.
Veber
B
B
Bedos
J P
JP
Gachot
B
B
Dombret
M C
MC
Regnier
B
B
Wolff
M
M
D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D018893:Bronchoalveolar Lavage / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D020680:Bronchoscopes; D001999:Bronchoscopy / Q000379:methods / Q000706:statistics & numerical data; D015169:Colony Count, Microbial; D016638:Critical Illness; D003428:Cross Infection / Q000188:drug therapy / Q000209:etiology / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000188:drug therapy / Q000209:etiology / Q000382:microbiology*; D011446:Prospective Studies; D013048:Specimen Handling / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D016896:Treatment Outcome; D012122:Ventilators, Mechanical / Q000009:adverse effects
D000900:Anti-Bacterial Agents